The matrix acidizing lab is used to simulate the acidizing process. Equipment mainly consists of the syringe pump; the brine/acid accumulator; the core holder; the data acquisition system; and the back pressure regulator. During the experiment, the syringe pump pushes the brine/acid out of the accumulators to the core. The pressure behavior is monitored by the data acquisition system.

The syringe pump is used to pump the fluids during experiment, either in constant flow rate mode or constant pressure mode. With two cylinders, it can continuously deliver flow rate, over a range of 0.1 ml/minute to 400 ml/minute, at a pressures range of from atmospheric to 7,500 psi. The accumulators are used to store brine/acid in the system. A Teflon piston is set inside the accumulator, which separates the accumulator into two chambers with one side filled with hydraulic oil and the other side filled with brine/acid. The core holder has three sizes: a 1-in diameter by 6-in length, a 1.5-in diameter by 20-in length, and a 4-in diameter by 20-in length. They have excellent corrosion resistance and capable to withstand a working pressure of 3,000 psi and temperatures of 300°F. The data acquisition system includes a pressure transducer, a NI signal processing board, and a computer installed with Labview software. It writes the pressure drop into a local file every 0.5 second. The back pressure regulator is used to create a pre-set fluid pressure before the experiment. It can support 6,000 psi pressure at maximum. This setup has been utilized to study the wormholing efficiency under different conditions. With high range back pressure regulator, the carbon dioxide behavior during acidizing can also be studied.

Overview of the matrix acidizing setup

Matrix acidizing setup featuring tall and wide area framed by square metal tubing suspending thin tubes, wires, large cylinders and instrumentation

Core holder

core holder supporting three horizontal large metal cylinders capped with metal ends and protruding wires